An estimated 3,000 trees were blown down in Vancouver's Stanley Park during a fierce windstorm on Dec. 15, 2006. (Richard Lam/Canadian Press)

Raging fires in Greek cities in the summer of 2007 focused the world's attention on the tenuous nature of urban forests. But in Canada the survival of individual trees in local neighbourhoods has become a greater concern.

Last December's devastating windstorm in Vancouver's Stanley Park took down thousands of trees. In Nova Scotia and Prince Edward Island in 2003, Hurricane Juan ripped up thousands of trees as it tore through landmarks including Halifax's Point Pleasant Park. Residents of Kelowna, B.C., watched helplessly that same year as fires destroyed their urban greenery. Montreal, western Quebec and eastern Ontario lost sugar maples, elms and other stately trees in the crippling ice storm of 1998.

Canada lags behind U.S.: expert

Tree Planting

Suggested trees for urban locations:

Halifax

Toronto

Calgary – Green ash, Elm (American and Brandon), Hawthorn, Bur Oak)

British Columbia

In fact, if you look at the number of trees felled by storms, bug infestations and bulldozed by developers, it might seem Canada's urban forests are in peril. Not so, says Ken Farr, a dendrologist and expert on urban forests with Canadian Forest Services.

"What's happening now is just part of nature," Far said. "Trees only live for so long. In some cities trees, like Norway maples, were planted to replace trees lost to Dutch elm disease in the 1920s and '30s. They're coming up to 100 years. For an urban tree that's a lot of stress and wear and tear."

That may be so, but experts in the field say it's time Canada took its urban forests as seriously as does the United States.

"If Americans are pioneers in urban forestry," said Andy Kenney, a senior lecturer in urban forestry at the University of Toronto, "Canadians are still at the hunter-gatherer stage, although there is a glimmer of hope. More municipalities are hiring people to deal with urban forest issues and some are embarking on long term strategic planning. However, without some long term vision or strategy, it's a hell of a way to manage a valuable resource."

Michael Rosen, president of the not-for-profit organization Tree Canada, agrees.

"Eighty per cent of Canadians live in urban areas, but the federal mandate in urban forestry has never been clear or obvious. Most other jurisdictions in the Western world consider their urban forests a priority. In Canada, it's kind of a curious sideline. It's difficult for municipalities to manage urban forests because the resources and the research aren't there. We often take our research from the States."

In fact, municipalities often spend their forestry budgets simply taking down trees or pruning damaged trees after storms, rather than investing in new planting.

Climate change, construction perils

Hotter, dryer summers and winters with lighter snowfalls, coupled with the fact that city trees have their own unique challenges make the survival of urban trees a more important issue than ever. Homeowners often pave over front lawns for parking, making it impossible to plant trees and difficult for trees nearby to live. Construction of monster homes, office buildings and condominiums means smaller trees and bushes are planted instead of big trees.

"You don't get the same environmental services from a small tree or bush that you get from a large tree in terms of energy saving and energy interception," Farr said.

As well, when developers create new subdivisions, topsoil is often scraped off and sold and new trees are planted in subsoil. Few high canopy trees can grow in substandard soil.

"All of our services — electricity, gas, cable, water and sanitary services — go into underground conduits," Rosen said. "They need to be serviced once every 10 or 15 years and when they are a lot of tree roots are ripped up. Trees die because of that."

National outlook

Trees in Canadian cities each have their own challenges. In British Columbia, English ivy (which smothers trees), wildfires and mountain pine beetles are a threat. Prairie cities such as Edmonton and Calgary lack sufficient water, leaving trees vulnerable to other diseases.

"Calgary spends a huge amount of money to water its trees," Rosen said. "It's not a place where trees originally grew so they have to be extremely innovative."

In Ontario, two invasive insects — the emerald ash borer and the Asian long-horned beetle — pose a serious threat.

Hurricane Juan's destruction was a huge blow to urban forests in the Maritimes. The streetscape is vastly different when a towering 100-year-old oak is replaced with a maple sapling.

"The way to respond to a range of risks and stresses is to have a range of trees and ages in the canopy," Farr said. Norway maple, green ash, little leaf linden, and honey locust are urban survivor trees."

Property lines: Green saves grey

Urban trees that provide lush canopies in parks, ravines and boulevards make a nice post-card picture, but the fact is most trees in cities are on private property. Kenney would like to see incentive programs making it easier and cheaper for homeowners to plant and maintain trees.

"If a community group figures out what they want their urban forest to look like and hires an arborist to maintain it, why shouldn't they receive financial compensation to offset the cost of it," Kenney said. "Already Ontario has a program for those in the country, who develop a plan for a woodland area. They can receive a substantial reduction in their property taxes. That would be great in the city."

Planting more trees is good for residents and the city itself. Trees in urban areas are necessary to absorb carbon dioxide and produce oxygen, knock pollutants out of the air, provide habitat for wildlife and help with energy conservation.

"A well positioned tree will save about 15-25 per cent off your energy bill by blocking cooling winds in the winter and creating shade to save on air conditioning in the summer," Rosen said.

As well, paved services (streets, sidewalks, parking lots, walkways, etc.) that are shaded from direct sunlight enjoy a longer lifecycle. Farr says,

"You're saving huge amounts in ‘grey' infrastructure by having ‘green' infrastructure," Farr said.

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